Enhanced fertility after heat-induced hyperactivation.
OBJECTIVE
To determine sperm hyperactivation, kinematic parameters, and fertilizing capacity after pretreating sperm at 40 degrees C for 4 hours.


METHODS
Prospective study involving pooled donor sperm that were colloid washed and incubated at either 23 degrees C (control) or 40 degrees C (heat-treated) for 4 hours as pretreatment. After incubation, analyses were performed with a computer-assisted sperm analyzer, whereas separate portions of sperm were evaluated with the sperm penetration assay at 37 degrees C.


METHODS
Clinical and academic research environment.


METHODS
Cryopreserved-thawed sperm from different donors (n = 5).


METHODS
Sperm kinematic and fertilizing parameters.


RESULTS
Heat pretreatment of sperm resulted in over 22 times higher hyperactive motility at hour 4 compared with the control. The other kinematic parameters were also different. The heat-pretreated sperm group had a significantly higher percent penetration of zona-free oocytes with more swollen sperm heads per oocyte and enhanced sperm binding.


CONCLUSIONS
The results showed that hyperactivation was induced by pretreatment of sperm with 40 degrees C heat, suggesting the involvement of heat factors in hyperactivation. The fertilizing capacity of sperm may be improved by the mild heat pretreatment when marked by the presence of heat-induced hyperactivation.
Chan
P J
PJ
Department of Gynecology and Obstetrics, Loma Linda University School of Medicine, California 92350, USA.
Corselli
J U
JU
Patton
W C
WC
Jacobson
J D
JD
King
A
A
D005260:Female; D005298:Fertility / Q000502:physiology*; D005306:Fertilization / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012016:Reference Values; D013081:Sperm Motility / Q000502:physiology; D013084:Sperm-Ovum Interactions / Q000502:physiology